feat(divergence): Jev noul restatement check -> harness review nudge (#25)

jev.go

@@ -252,6 +252,61 @@ func (j *JevClient) ClassifyKind(ctx context.Context, text string) (string, map[
 	return a.Choice, a.Probabilities, true
 }
 
+// divergenceQuestions asks whether a message restates an earlier point. It is
+// a noul: JEV_STRATEGIES strategy 3 (crisp yes/no) and noul has no confidence,
+// so the probability itself is thresholded (band = threshold).
+var divergenceQuestions = map[string]any{
+	"restates_earlier": map[string]any{
+		"type":         "noul",
+		"instructions": "Does `this` make a point already made in `earlier`, adding no new angle?",
+		"criteria": map[string]string{
+			"true":  "It repeats an earlier point without a genuinely new angle.",
+			"false": "It adds something different from what `earlier` already said.",
+		},
+	},
+}
+
+// ClassifyDivergence returns the probability that a message restates earlier
+// ones, and ok when a value came back (noul always carries one; ok is false
+// only on transport error or a missing answer).
+func (j *JevClient) ClassifyDivergence(ctx context.Context, state any) (float64, bool) {
+	if j == nil {
+		return 0, false
+	}
+	answers, _, _, err := j.SystemOne(ctx, state, divergenceQuestions)
+	if err != nil {
+		return 0, false
+	}
+	a := answers["restates_earlier"]
+	if a.Noul == nil {
+		return 0, false
+	}
+	return *a.Noul, true
+}
+
+// ClassifyDivergence runs the restatement check under the flock guardrails
+// (cap, timeout, flight log with the probability recorded).
+func (f *Flock) ClassifyDivergence(ctx context.Context, state any, budgets ...*Budget) (float64, bool) {
+	if f.jev == nil {
+		return 0, false
+	}
+	for _, b := range budgets {
+		if err := b.Check(); err != nil {
+			return 0, false
+		}
+	}
+	f.sem <- struct{}{}
+	defer func() { <-f.sem }()
+	cctx, cancel := context.WithTimeout(ctx, f.g.CrowTimeout)
+	defer cancel()
+	start := time.Now()
+	p, ok := f.jev.ClassifyDivergence(cctx, state)
+	if f.log != nil {
+		f.log.Write(Event{Kind: "divergence", Crow: "Sentry", Model: f.jev.model, Ms: time.Since(start).Milliseconds(), Prob: map[string]float64{"restates_earlier": p}, Note: fmt.Sprint(ok && p >= f.jev.threshold)})
+	}
+	return p, ok
+}
+
 // ClassifyKind tags a nest message under the same guardrails as any call:
 // flock cap, timeout and flight log, with the probabilities recorded.
 func (f *Flock) ClassifyKind(ctx context.Context, text string, budgets ...*Budget) (string, map[string]float64, bool) {

nestapi.go

@@ -184,6 +184,10 @@ func (s *Server) postNestMessage(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	if kind == "deliver" {
+		go s.checkDivergence(nest, record)
+	}
+
 	writeJSON(w, http.StatusCreated, nestRecord(record))
 }
 
@@ -298,6 +302,42 @@ func (s *Server) respondOne(nest Nest, req Message, crow string, lens bool) {
 	}
 	if record, err := s.msgs.Append(reply); err == nil {
 		s.emitNestMessage(record)
+		if record.Kind == "deliver" {
+			s.checkDivergence(nest, record)
+		}
+	}
+}
+
+// checkDivergence asks Jev whether this deliver restates earlier delivers that
+// answer the same request. Above the band the crow gets a review nudge; the
+// deliver itself stays in the log (nudges never silence).
+func (s *Server) checkDivergence(nest Nest, m Message, budgets ...*Budget) {
+	if m.Kind != "deliver" {
+		return
+	}
+	earlier := s.msgs.EarlierDelivers(nest.ID, m.RefersTo, m.ID)
+	if len(earlier) == 0 {
+		return
+	}
+	if _, nudged := s.msgs.NudgeFor(nest.ID, m.MsgID()); nudged {
+		return // one nudge per deliver; no loop
+	}
+	prob, ok := s.p.Flock.ClassifyDivergence(s.ctx, map[string]any{"this": m.Text, "earlier": earlier}, budgets...)
+	if !ok || prob < s.p.Flock.jev.threshold {
+		return
+	}
+	nudge := Message{
+		NestID:    nest.ID,
+		Kind:      "nudge",
+		Author:    "harness",
+		Text:      "This reads like a point already made in the thread; review the earlier delivers and add your distinct angle or let it rest.",
+		To:        m.Author,
+		RefersTo:  m.MsgID(),
+		TaggedBy:  "harness",
+		Timestamp: time.Now().UTC().Format(time.RFC3339),
+	}
+	if record, err := s.msgs.Append(nudge); err == nil {
+		s.emitNestMessage(record)
 	}
 }
 

nestlog.go

@@ -132,6 +132,32 @@ func (s *MessageStore) FirstClaim(nestID, referentID string) (string, bool) {
 	return "", false
 }
 
+// EarlierDelivers returns the texts of deliver messages answering the same
+// referent, oldest first, excluding the one with id excludeID.
+func (s *MessageStore) EarlierDelivers(nestID, referentID string, excludeID int) []string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	var out []string
+	for _, m := range s.log[nestID] {
+		if m.Kind == "deliver" && m.RefersTo == referentID && m.ID != excludeID {
+			out = append(out, m.Text)
+		}
+	}
+	return out
+}
+
+// NudgeFor reports whether a nudge already references a given message.
+func (s *MessageStore) NudgeFor(nestID, targetMsgID string) (Message, bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for _, m := range s.log[nestID] {
+		if m.Kind == "nudge" && m.RefersTo == targetMsgID {
+			return m, true
+		}
+	}
+	return Message{}, false
+}
+
 func (s *MessageStore) save(nestID string) error {
 	if err := os.MkdirAll(s.dir, 0o755); err != nil {
 		return err